Control of ATP concentration in Escherichia coli using an ATP-sensing riboswitch for enhanced S-adenosylmethionine production

Abstract

ATP is the limiting precursor for S-adenosylmethionine (SAM) synthesis in Escherichia coli. In contrast to traditional optimization of fermentation processes, the riboswitch-based strategy, which was developed as a novel efficient regulation approach, has been applied for the control of the intracellular ATP concentration in order to promote the production of SAM. In this work, a newly discovered ATP-sensing riboswitch ydaO motif was used to balance the requirement of ATP in SAM biosynthesis. The results show that the RNA element ydaO from Bacillus subtilis could play a role in regulating gene expression in E. coli. The ydaO motif-based regulation strategy, which was induced by ATP, improved the ATP level as well as the titer of SAM. The intracellular SAM titer of the best-performing strain, AYV, produced the highest SAM titer (1.23 mg L⁻¹) which was increased by about 55% compared with the control. Overall, the method enabled new insights into the regulation of ATP in E. coli. These results demonstrate a strategy for optimally employing an ATP-sensing riboswitch for the ATP balance of industrial ATP-driven bioprocesses.